net/sunrpc/auth_generic.c

   1 /*
   2  * Generic RPC credential
   3  *
   4  * Copyright (C) 2008, Trond Myklebust <Trond.Myklebust@netapp.com>
   5  */
   6
   7 #include <linux/err.h>
   8 #include <linux/slab.h>
   9 #include <linux/types.h>
  10 #include <linux/module.h>
  11 #include <linux/sched.h>
  12 #include <linux/sunrpc/auth.h>
  13 #include <linux/sunrpc/clnt.h>
  14 #include <linux/sunrpc/debug.h>
  15 #include <linux/sunrpc/sched.h>
  16
  17 #ifdef RPC_DEBUG
  18 # define RPCDBG_FACILITY        RPCDBG_AUTH
  19 #endif
  20
  21 #define RPC_MACHINE_CRED_USERID         ((uid_t)0)
  22 #define RPC_MACHINE_CRED_GROUPID        ((gid_t)0)
  23
  24 struct generic_cred {
  25         struct rpc_cred gc_base;
  26         struct auth_cred acred;
  27 };
  28
  29 static struct rpc_auth generic_auth;
  30 static const struct rpc_credops generic_credops;
  31
  32 /*
  33  * Public call interface
  34  */
  35 struct rpc_cred *rpc_lookup_cred(void)
  36 {
  37         return rpcauth_lookupcred(&generic_auth, 0);
  38 }
  39 EXPORT_SYMBOL_GPL(rpc_lookup_cred);
  40
  41 /*
  42  * Public call interface for looking up machine creds.
  43  */
  44 struct rpc_cred *rpc_lookup_machine_cred(void)
  45 {
  46         struct auth_cred acred = {
  47                 .uid = RPC_MACHINE_CRED_USERID,
  48                 .gid = RPC_MACHINE_CRED_GROUPID,
  49                 .machine_cred = 1,
  50         };
  51
  52         dprintk("RPC:       looking up machine cred\n");
  53         return generic_auth.au_ops->lookup_cred(&generic_auth, &acred, 0);
  54 }
  55 EXPORT_SYMBOL_GPL(rpc_lookup_machine_cred);
  56
  57 static struct rpc_cred *generic_bind_cred(struct rpc_task *task,
  58                 struct rpc_cred *cred, int lookupflags)
  59 {
  60         struct rpc_auth *auth = task->tk_client->cl_auth;
  61         struct auth_cred *acred = &container_of(cred, struct generic_cred, gc_base)->acred;
  62
  63         return auth->au_ops->lookup_cred(auth, acred, lookupflags);
  64 }
  65
  66 /*
  67  * Lookup generic creds for current process
  68  */
  69 static struct rpc_cred *
  70 generic_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  71 {
  72         return rpcauth_lookup_credcache(&generic_auth, acred, flags);
  73 }
  74
  75 static struct rpc_cred *
  76 generic_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
  77 {
  78         struct generic_cred *gcred;
  79
  80         gcred = kmalloc(sizeof(*gcred), GFP_KERNEL);
  81         if (gcred == NULL)
  82                 return ERR_PTR(-ENOMEM);
  83
  84         rpcauth_init_cred(&gcred->gc_base, acred, &generic_auth, &generic_credops);
  85         gcred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
  86
  87         gcred->acred.uid = acred->uid;
  88         gcred->acred.gid = acred->gid;
  89         gcred->acred.group_info = acred->group_info;
  90         if (gcred->acred.group_info != NULL)
  91                 get_group_info(gcred->acred.group_info);
  92         gcred->acred.machine_cred = acred->machine_cred;
  93
  94         dprintk("RPC:       allocated %s cred %p for uid %d gid %d\n",
  95                         gcred->acred.machine_cred ? "machine" : "generic",
  96                         gcred, acred->uid, acred->gid);
  97         return &gcred->gc_base;
  98 }
  99
 100 static void
 101 generic_free_cred(struct rpc_cred *cred)
 102 {
 103         struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
 104
 105         dprintk("RPC:       generic_free_cred %p\n", gcred);
 106         if (gcred->acred.group_info != NULL)
 107                 put_group_info(gcred->acred.group_info);
 108         kfree(gcred);
 109 }
 110
 111 static void
 112 generic_free_cred_callback(struct rcu_head *head)
 113 {
 114         struct rpc_cred *cred = container_of(head, struct rpc_cred, cr_rcu);
 115         generic_free_cred(cred);
 116 }
 117
 118 static void
 119 generic_destroy_cred(struct rpc_cred *cred)
 120 {
 121         call_rcu(&cred->cr_rcu, generic_free_cred_callback);
 122 }
 123
 124 /*
 125  * Match credentials against current process creds.
 126  */
 127 static int
 128 generic_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
 129 {
 130         struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
 131         int i;
 132
 133         if (gcred->acred.uid != acred->uid ||
 134             gcred->acred.gid != acred->gid ||
 135             gcred->acred.machine_cred != acred->machine_cred)
 136                 goto out_nomatch;
 137
 138         /* Optimisation in the case where pointers are identical... */
 139         if (gcred->acred.group_info == acred->group_info)
 140                 goto out_match;
 141
 142         /* Slow path... */
 143         if (gcred->acred.group_info->ngroups != acred->group_info->ngroups)
 144                 goto out_nomatch;
 145         for (i = 0; i < gcred->acred.group_info->ngroups; i++) {
 146                 if (GROUP_AT(gcred->acred.group_info, i) !=
 147                                 GROUP_AT(acred->group_info, i))
 148                         goto out_nomatch;
 149         }
 150 out_match:
 151         return 1;
 152 out_nomatch:
 153         return 0;
 154 }
 155
 156 int __init rpc_init_generic_auth(void)
 157 {
 158         return rpcauth_init_credcache(&generic_auth);
 159 }
 160
 161 void rpc_destroy_generic_auth(void)
 162 {
 163         rpcauth_destroy_credcache(&generic_auth);
 164 }
 165
 166 static const struct rpc_authops generic_auth_ops = {
 167         .owner = THIS_MODULE,
 168         .au_name = "Generic",
 169         .lookup_cred = generic_lookup_cred,
 170         .crcreate = generic_create_cred,
 171 };
 172
 173 static struct rpc_auth generic_auth = {
 174         .au_ops = &generic_auth_ops,
 175         .au_count = ATOMIC_INIT(0),
 176 };
 177
 178 static const struct rpc_credops generic_credops = {
 179         .cr_name = "Generic cred",
 180         .crdestroy = generic_destroy_cred,
 181         .crbind = generic_bind_cred,
 182         .crmatch = generic_match,
 183 };